Electron discharge device



Nov. 8, 1949 e. L. RISHELL 2,487,592

ELECTRON DI S CHARGE DEVICE Filed Feb. 6, 1948 I JNVENTORQ 61901 5712 L. fib'jizell Patented Nov. 8, 1949 ELECTRON DISCHARGE DEV-ICE George L. 'Rishell, Emporium, Pa", assignor to Sylvania Electric Products of Massachusetts 1110., a corporation Application February 6, 1948, Serial No. 6,591

6 Claims. 1

This invention relates to electron discharge devices. Their structure conventionally comprises an electron emitting source, one or more .gr'id elements and an anode. The characteristics of the device are importantly affected by the positions of the various electrodes with respect to one another, in radial and endwise directions. The electrodes are arranged to form an :assembly which is enclosed in an envelope having leads sealed through the wall thereof for connecting the electrodes to external circuits. In constructing a tube, a large number of welds are made between the electrodes and the associated leads and it is important that all Welds be well made and that the electrodes be retained firmly in place for noise-free operation.

The relative radial position of the electrodes are fixed by electrode extensions which penetrate suitably apertured transverse insulating wafers. The endwise position of the electrodes and especially of grid electrodes are fixed by welding them to rigid metal members secured to one of the insulating wafers when such electrodes are in proper endwise locations. According to one prior art practice, the rigid member is riveted to the insulating wafer. The additional aperture in the wafer required by the rivet and the riveting process both tend to weaken the insulating vvaier.

In prior art practice large number of Welds which is required to connect the electrodes to the external leads and to the electrode locators :or grid stops are a potential source of defective tubes.

An object, therefore, of my invention is the "reduction of the number of welds used in the construction of electron discharge devices.

A :further object is to provide an improved electrode locator.

Another more general object is to improve the construction of electron tubes in respect toendwise locators for electrodes and connectors joining the electrodes to the sealed-through leads.

.In practicing one feature of my invention 'a single piece of metal is utilized both as electrode, or electrode locato'r and as the connecting wire between the electrode and the associate lead. This reduces the number of welds in the electron tube. In another aspect of my invention, a grid stop or electrode locator is providedwi-th a lug to grip the insulating wafer, thereby eliminating the anode tor riveting parts together.

In accordance with another feature of my invention, an electrode stop is mounted close to a lead sealed through the envelope, enabling use of short leads between the electrode and the associated lead, with resulting improved high frequency characteristics.

.In a further aspect of my invention, a beamforming electrode is formed with an integral connecting strap to'retain the electrode in proper endwise position and to provide a conductive link to its associated lead.

A better understanding of the invention including further features of novelty will be ai- 'forded by the following detailed description considered in connection with the accompanying drawing, and those features of the invention which are believed to be novel and patentable will be pointed "out in the appended claims.

Figure 1 is a View in elevation of a lock-in electron discharge tube of a type in which the present invention maybe used.

Figure '2 is a sectional view on line 22 of Figure 3, part of the envelope also being shown.

Figure 3 is a View of an assembled electrode mount with the envelope removed and with part of the anode, No, 2 grid, and beam-forming plates broken away.

Figure 4 is a sectional view on line 4-4 of Figure 3.

Figures 5 and 6 are views in perspective of two grid stops.

Figure 7 is :a view in perspective of a beamforming electrode having an integral strap connector.

The electron tube of Figure 1, shown for illustrative purposes only, has an envelope H, a header l2 and base pins l3a-c penetrating said header 12.

Further, merely 'for purposes of illustration, an electrode assembly 14 is mounted within the envelope as shown in Figure 3 and includes a filament 1'5, cathode It, a first grid il, a second grid l8, beam-forming plates 9, and an anode 49, in nested array. The laterals of grid I! are mounted on upright supports or side rods 20 and 21, the .grid laterals of grid -I8 being similarly mounted on supports 22 and 23.

Radial spacing of the grid laterals is deterznined'by fitting the extremities of rods 2!], 2i and 22, 23 through suitably formed and located apertures in transverse insulating Waters 2 1 and 25. The ultimate mutual positioning of the grids "is further established by an endwise movement of the upright supports 20, 2| and 22, 23 until the desired electrode relationship is obtained, after which the rods are restricted in endWise movement by welding one extremity of each rod to a stop. 'I-lere'tofore the other extremity of the support rod has been used as a connecting point :Eor .a conductive strap to suitable base pins or leads such as [3a, b, 0.

My grid stop is formed of a unitary piece of metal 26 (Figs. 5 and 6 in which similar numeral designations .refer to equivalent parts thereof) provided with lug portions '21 and 2B, tongue extension portions .29, 3.0 and a conducting strap portion of suitable shape and length 3 l For the purpose of illustrating my invention,

reference is made to Figure 4, wherein the stop member is mounted on insulating wafer 24 by bending the lugs 21, 28 over a suitably formed portion of said wafer after which the tongues 29 and so are welded to the extremities of second grid'side rods 22 and 23, respectively, and the conductive strap 3| is welded to a suitable pin 13a. The lugs 2? and 28 are advantageously preformed as channels for slidably mounting the stop on the insulating wafer, eliminating additional operations on the mica and providing gripping means for retaining the wafer and stop in position.

Grid stop 26a is mounted in a manner similar to stop 25 with the connecting strap 31a suitably preformed to reach associated pin lSb.

A connecting tab 32, comparable to tab 31 or 31a, is formed as an integral portion of a beamforming electrode 9 (Figure '7). The electrode 9 is mounted in the electrode assembly Hi and connecting strap 32 is welded to associated pin I30 which extends through wafer 24. By virtue of this construction one weld between the electrode and the associated pin serves where two or more were previously needed. It is evident that the pins l3a, b, c are in circular array, and that the pin 130 to which the beam-forming plate 9 is to be connected is beyond the radial limit of the electrode assembly. Strap 32, therefore, is arranged to extend partly across wafer 24 opposite straps 3| and Sta, and an aperture 33 is provided in anode l9 to accommodate strap 32. Wafer 24 thus serves to separate the connecting means that join the electrodes severally with their leads I3a, b, 0.

While I have shown and described certain preferred embodiments of my invention, it will be understood that modifications and changes may be made without departing from the spirit and scope thereof, as will be clear to those skilled in the art.

anode,'one of said leads extending through said wafer, said anode having an aperture, and said beam--forming electrode connector strap extending partly across said wafer through said anode aperture and connected to said one of said leads.

2. An electron tube comprising an envelope, .a plurality of leads sealed through said envelope, and an electrode assembly within said envelope, said electrode assembly comprising a wafer and a plurality of electrodes mounted on said wafer, said electrodes including a beam-forming electrode having an integral strap portion, and an anode, one of said leads extending through said Wafer, said anode having an aperture, and said beam-forming electrode connector strap extending partly across said wafer through said anode aperture and connected to said one of said leads, another of said electrodes having a supporting rod passing through said wafer, a stop member secured to said rod and having a fiat portion lying against said wafer, there being a number of lugs on said flat portion embracing a portion of said wafer.

3. An electron tube comprising an envelope, a plurality of leads sealed through said envelope, and an electrode assembly within said envelope,

said electrode assembly comprising a wafer and a plurality of electrodes mounted on said wafer, said electrodes including a beam-forming electrode having an integral strap portion, and an anode, one of said leads extending across said wafer, said anode having an aperture, and said beam-forming electrode connector strap connected to said lead extending across said wafer, through said anode aperture, another of said electrodes having a supporting rod passing through said wafer, a stop member secured to said rod and having a flat portion lying against said Wafer, there being a number of lugs on said flat portion embracing a portion of said Wafer, and an integral tongue connected to one of said leads.

4. An electron discharge tube comprising an envelope, a plurality of leads through said envelope, and an electrode assembly within said envelope, said electrode assembly comprising an insulating wafer, a plurality of electrodes including a first grid and a second grid, said electrodes held in mutually spaced position by said wafer, a first stop member having integrally connected parallel portions on opposite sides of said wafer and integral portions secured to said first grid and one of said leads, a, second stop member having integrally connected parallel portions on opposite sides of said wafer and spaced apart from said first stop member, and integral portions connected to said second grid and to another of said leads.

5. An electron tube comprising an envelope, a plurality of leads sealed through said envelope, and an electrode assembly within said envelope, said electrode assembly including an insulating wafer and a plurality of nested electrodes fixed in relative position by said wafer, and connections between said leads and said nested electrodes on opposite sides of said wafer, the outermost of said electrodes having a cut away portion adjacent said wafer to clear a connection between an inner one of said nested electrodes and one of said leads.

6. An electron discharge tube comprising an envelope, a plurality of leads sealed through said envelope and an electrode assembly Within saidenvelope, said electrode assembly comprising an insulating wafer, a plurality of electrodes, including a grid electrode, held in mutually spaced position by said water, and a. stop member having a fiat portion lying against one side of said wafer and having lug portions bent to embrace portions of said wafer in the form of substantially parallel integral portions on opposite side of said wafer and integral portions secured to said grid electrode and to one of said leads, and integral bent up lugs secured to part of said grid electrode.

GEORGE L. RISHELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,866,715 Krahl June 12, 1932 1,869,568 Krahl Aug. 2, 1932 2,254,096 Thompson Aug. 26, 1941 2,396,170 Fulton, Jr Mar. 5, 1946 2,427,888 Warren Sept. 23, 1947 2,445,411 Stratton July 20, 1948 

